This invention relates to a surgical device for lifting tissue to create an operative space in a patient for facilitating the performance of a surgical procedure. It also relates to a method of performing a surgical procedure within the patient using a surgical device to create or enlarge the operative space.
During conventional endoscopic surgery, the abdominal cavity of the patient is inflated to provide an operative space between the surgical site and adjacent bodily organs. In the conventional procedure, carbon dioxide gas is pumped into the abdominal cavity to raise the abdominal wall and create the operative space necessary to carry out the endoscopic procedure. Once the abdominal cavity is sufficiently "insufflated" with carbon dioxide gas, the desired diagnostic or therapeutic procedure can be performed with the use of instruments capable of the desired surgical manipulations at the surgical site. These instruments are sealed to prevent or minimize the escape of insufflation gas during the procedure.
Although carbon dioxide insufflation has provided an acceptable methodology for creating an operative space in the abdominal cavity during endoscopic surgery, it does have its drawbacks. When the insufflation gas is pumped into the abdominal cavity, it is pumped into the cavity at a pressure higher than that of the atmosphere in the room. This creates a positive pressure differential between the gas inside the abdominal cavity and the ambient room atmosphere, consequently exerting a force on the internal tissue structures within the abdominal cavity. The disadvantages of this phenomenon during the surgical procedure include the following:
a) pressure on the vena cava can reduce cardiac output, PA1 b) pressure on the diaphragm can cause phrenic nerve irritation and reduced respiratory function, PA1 c) carbon dioxide absorption may increase the need for ventilation, PA1 d) potential hypercarbia and blood acidosis in respiratory compromised patients, and PA1 e) tissue desiccation and cooling due to the dry cold gas present in the abdominal cavity.
There are other practical limitations with the use of carbon dioxide insufflation as well. These include the expense of the system for storing and pumping the gas into the abdominal cavity, and the difficulties when using suction during the surgical procedure to c lea r smoke or fluids from the operative site. Unfortunately, when suction is used inside the abdominal cavity for those purposes, it will naturally remove the carbon dioxide gas, decreasing the positive pressure inside the abdomen, thus sometimes causing a loss in the proper lift of the abdominal wall.
In view of the drawbacks attendant with carbon dioxide insufflation during endoscopic surgery, alternatives to this methodology have been proposed. In particular, numerous patents have been published which describe various mechanical lifts which are designed to elevate the abdominal wall during an endoscopic procedure to create the operative space. Examples of patents in this area are U.S. Pat. Nos. 5,309,896; 5,361,752; 5,402,772; 5,425,357; 5,450,843; 5,454,367; 5,465,711; 5,501,653; 5,505,689; 5,514,075; 5,520,609; 5,522,790; 5,527,264; 5,531,856; 5,562,603; 5,569,165; 5,575,759; 5,632,761; 5,634,883; 5,643,178; 5,676,636; 5,681,341; 5,690,607; 5,716,327 and 5,836,871. The mechanical wall lift devices described in these patents typically are initially inserted into the abdominal cavity, and then actuated to physically lift the interior tissue surfaces of the abdominal wall. In certain illustrated embodiments, balloon structures are designed to inflate inside the abdominal cavity and lift the interior abdominal wall. These balloon structures act like car jacks to separate the abdominal wall from the internal tissues. In other embodiments, "fan blade" style retractors operate by means of an external lifting mechanism, such as a mechanical lifting arm. The fan blades are attached to the lifting arm and then inserted into the abdominal cavity. The arm is then activated and then pushes against the abdominal wall to lift it.
Other examples of patents describing devices which mechanically lift the abdominal wall to provide an operative space include U.S. Pat. Nos. 5,398,671; 5,415,159; 5,415,160; 5,545,123; 5,183,033; 5,318,012; 5,353,785; 5,601,592; 5,716,326 and 5,613,939.
Although the mechanical wall lifting devices provide an alternative to conventional carbon dioxide insufflation, these devices have some significant drawbacks. A major drawback is that these devices must be initially deployed in the interior abdominal cavity and then actuated to lift the abdominal wall for creating the operative space. Unfortunately, these devices tend to be bulky and can create a significant obstruction in the cavity for the surgeon, thus making the performance of the desired operative procedure at the surgical site more difficult. The mechanical devices also require a bulky hoist mechanism that must be attached to the operating table or other support structure, or a surgical assistant must hold the abdomen up using direct upward muscular force. Further, the mechanical devices create less operative space than is needed to complete many surgeries because the space created with these devices is shaped more like a "tent" than a dome.
With respect to the mechanical devices which include an inflatable balloon, once the balloon is inflated, it will create direct pressure on internal tissue structures within the abdominal cavity. This direct pressure can cause problems, for example, reduced blood flow, or a reduction in excursion of the diaphragm with respiration. The "fan blade" retractor designs and methods apply a force near the incision site on the abdominal wall. The tissue surface area affected by the fan blade is small, thus significantly increasing the contact stress on the tissue, and potentially resulting in tissue damage.
Another device for lifting the abdominal wall to create an operative space within the abdominal cavity is described in U.S. Pat. No. 4,633,865. This device uses vacuum to lift the abdominal wall to perform examinations and surgical interventions within the abdominal cavity. The device consists of a cowling that is hermetically sealed against the exterior abdominal wall. The cowling has a central opening with an annular projection directed inwardly. The opening is temporarily closed using a lid, and vacuum is applied between the inner surface of the cowling and the exterior abdominal wall, causing the abdominal wall to be raised toward the cowling. With the wall raised toward the cowling, the lid over the central opening is removed and the abdominal wall can then be pierced. Subsequently, the lid covering the opening in the cowling can be removed, and instruments may be inserted through the opening, and into the abdominal cavity for examination and surgical interventions.
Although this device eliminates the need for carbon dioxide insufflation and represents an alternative to the mechanical wall lifts which must be deployed within the interior of the abdominal cavity, it has some significant drawbacks. The most significant drawback is that when the abdominal wall is lifted upon application of vacuum, the internal organs within the abdominal cavity will lift upwardly in tandem with the upward movement of the abdominal wall. This is so because a negative pressure develops in the abdominal cavity when the vacuum is applied to the exterior wall. As a result of this negative pressure created in the abdominal cavity, the internal organs will be displaced, and consequently lifted upwardly as the abdominal wall is lifted. As a result, the internal organs do not fall away and will remain positioned adjacent the abdominal wall. Consequently, the desired operative space between the abdominal wall and the internal organs for effectively carrying out the endoscopic surgical procedure will not be provided, and serious injury to these internal organs may occur during the surgical procedure if the required operative space is not created.
Another drawback to the vacuum-assisted device illustrated in U.S. Pat. No. 4,633,865 is that it does not describe an adequate mechanism for maintaining a vacuum seal to ensure adequate abdominal lift when a surgical instrument is inserted through the opening in the cowling and into the abdominal cavity during the endoscopic surgical procedure.
In view of the deficiencies inherent in the prior art devices for lifting the abdominal wall during an endoscopic surgical procedure to create an operative space, a device is needed which will address these inherent deficiencies. Specifically, the device and its method of use will eliminate the requirement for carbon dioxide insufflation of the abdominal cavity. Additionally, it will not create obstructions or barriers within the interior operative space, thus reducing surgeon inconvenience and patient risk. Further, the ideal device will lift the desired tissue without creating unwanted displacement of internal organs, ensuring that appropriate space between the lifted tissue and the internal organs is created. This ideal instrument would also preferably have the capability to provide and maintain lift even when surgical instruments or human digits are inserted through it to reach the surgical site, and the ability to have internal organs temporarily externalized through it while maintaining lift. Further, the ideal device will have at least one receptacle which is suitable for attaching and holding the various surgical instruments (including cameras) which the surgeon may employ, freeing the hands of the surgeon or assistant. Finally, it would certainly be advantageous if such a device were created which could be employed using less expensive surgical instruments which do not require seals to maintain an insufflated abdominal space or other operative space during the surgical procedure.